The prior art teaches receptacles with projections extending from the open end for holding bags. The following two patents are examples:
McCarthy U.S. Pat. No. 4,867,328 teaches a sectionized receptacle comprising a receptacle with either a round or rectangular horizontal cross section for positioning a plurality of bags of flexible material and projections of which one or more are used to support and hold the upper open end of the bags. McCarthy teaches his projections as being adjacent the upper open end of the receptacle and that they extend vertically away from the receptacle.
Preston U.S. Pat. No. 4,735,340 teaches a trash bag bracket for use on trash receptacles comprising a group of two brackets which are attached to the upper open end of a receptacle and extend vertically upward and away from the open end for positioning and holding a bag of flexible material.